The integrated circuitry (IC) industry is currently researching and developing new metallic interconnect materials and structures which can be used within integrated circuits (ICs). A promising metallic material which will be used in the future for integrated circuit (IC) interconnects is copper (Cu). Copper is desired in the integrated circuit industry since copper has improved electromigration resistance over aluminum and other metallic materials which are currently being used in the integrated circuit industry. In addition, copper has a lower resistivity than other commonly used metallic materials, whereby the performance of integrated circuit devices can be greatly improved through the use of copper interconnects.
However, there is currently no known technology which can effectively plasma etch or wet etch copper materials so that functional copper interconnects are adequately formed over the surface of an integrated circuit. In order to overcome this limitation, copper chemical mechanical polishing (CMP) has been suggested as the most promising alternative which can render proper formation of copper interconnects on an integrated circuit. Therefore, the industry is currently searching for an optimal chemical mechanical polishing (CMP) slurry which can be used to form copper interconnects on an integrated circuit (IC).
It is known in the industry to use one of either H.sub.2 O.sub.2 or H.sub.3 PO.sub.4 as an oxidizing agent in a slurry in order to perform aluminum polishing. It is also known in the art to use one of H.sub.2 O.sub.2, KIO.sub.3, Ce(NO.sub.3).sub.4, Fe(NO.sub.3).sub.3, and K.sub.3 Fe(CN).sub.6 to polish tungsten material. It is also known to use one of HNO.sub.3, HN.sub.4 OH, or KMnO.sub.4 to perform polishing of copper. Therefore, these chemical compounds have been extensively researched by CMP engineers in an attempt to discover an optimal copper CMP process. However, the use of these known chemicals has not yet produced optimal copper polishing results.
For example, various experimentation performed using the known chemistries described above have resulted in one or more of: (1) poor removal rate whereby CMP throughput is inadequate; (2) excessive pitting and/or corrosion of the copper material whereby device performance and device yield is reduced; (3) layer planarity problems; (4) poor IC electrical performance; or (5) poor selectivity to copper over adjacent oxide materials ("oxide" refers to "silicon dioxide" and the two may be used interchangeably herein.)
Therefore, a need exist in the industry for an improved CMP slurry which may be used to manufacture copper interconnects while reducing or eliminating one or more of the above common copper CMP problems. This improved slurry should have good removal rate whereby CMP throughput is improved, reduced or eliminated pitting and corrosion of the copper material whereby device performance and yield is improved, improved planarity of the copper layer, improved electrical performance of integrated circuits, and/or improved selectivity of copper to oxide.